Mounting apparatus and mounting method

ABSTRACT

A mounting apparatus includes: a heater head for bonding a liquid crystal display and a flexible printed circuit board by thermocompression; a cylinder as a heater head driving means for driving heater head to compress the liquid crystal display and flexible printed circuit board by a prescribed load; and a control mechanism as a stretch amount controlling means for adjusting a load change per unit of time after the heater head starts compressing the flexible printed circuit board by the cylinder as well as a time at which a required load is attained to control the stretch amount of the flexible printed circuit board by thermocompression. Preferably, the mounting apparatus is provided with a mechanism which performs measurement after preliminary bonding and which performs regular bonding while controlling based on the obtained information.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a mounting apparatus and mountingmethod of mounting a flexible board onto a display board. Specifically,the mounting refers to electrically connecting terminal electrode rows.For example, the present invention relates to a mounting apparatus andmounting method of connecting a terminal electrode of a TFT (Thin FilmTransistor) liquid crystal display and a terminal electrode of a TCP(Tape Carrier Package) of a flexible printed circuit board mounted withan LSI (Large Scale Integrated circuit) for driving.

2. Description of the Background Art

Referring to FIGS. 10 and 11, a conventional method of connecting aliquid crystal display 2 containing a liquid crystal layer 1 and aflexible printed circuit board 4 mounted with an LSI for driving will bedescribed. In connecting, as shown in FIG. 10, a terminal electrode 3 ofliquid crystal display 2 and a terminal electrode 5 of flexible printedcircuit board 4 are bonded together, for example by thermocompressionthrough an adhesive agent 6. For thermocompression, a cylinder-drivenheater tool 8 is lowered and pressed.

FIG. 11 shows the structure of FIG. 10 viewed from above, where theterminal electrodes are bonded by thermocompression. It is generallyknown that flexible printed circuit board 4 stretches duringthermocompression. It appears in FIG. 11 that terminal electrodes 3 and5 are perfectly in alignment. However, it can be seen in FIG. 12,showing in enlargement outermost terminal electrodes 3 and 5, thatterminal electrode 5 is displaced by a displacement amount 7 in theelectrode width direction according to a stretch amount of flexibleprinted circuit board 4.

A common practice to adjust the stretch amount of flexible printedcircuit board 4 is that an operator measures displacement amount 7 withuse of a microscope or the like, and repeats thermocompression withdifferent parameters of compressing temperature, pressure, time and soon to determine displacement amount 7. Thus, the operator must gothrough a continuing process of trial and error to find appropriateconditions for thermocompression.

Particularly, conventional terminal electrodes have a large pitch toallow for stretching of the flexible printed circuit board. In addition,a specific method of controlling the stretch amount of flexible printedcircuit board has been unknown. For these reasons, in the conventionalapparatuses, variation in stretch amount according to a material or sizeis restrained based on personal judgement and experience of an operator,for example, by varying an air flow as a variable parameter to adjustthe lowering speed of a heater tool.

In recent years, flexible printed circuit boards are becoming moresophisticated and the pitch of terminal electrodes is reducedaccordingly. This leads to the need for properly estimating the stretchamount of flexible printed circuit boards. Thus, the conventionalmounting method is no longer satisfactory.

The above described conventional mounting technique suffers from threemajor problems.

First, the adjustment of the compressing temperature, pressure and timeby cylinder-driven heater tool 8 is based on personal judgement andexperience of the operator, whereby the stretch amount of flexibleprinted circuit board 4 is not quantitatively adjusted in the optimummanner with respect to the required adjustment amount. Depending on theskill level of the operator, such adjustment usually involves aconsiderable amount of time. Thus, the method is not satisfactory if theadjustment must be made in a short period of time.

Secondly, cylinder-driven heater tool 8 involves a long stroke. Thus,pressure variation in the cylinder is large and a load applied to anobject fluctuates. Note that the compression pressure is obtained bydividing the load by an area subjected to compression. This causesvariation is stretch amount and displacement inconsistency of terminalelectrodes 3 and 5. As such, the conventional technique cannot fullycope with reduced pitches of terminal electrode rows to be connected.

Thirdly, the measurement of displacement amount 7 must be made by theoperator with use of a microscope since an image processing apparatusesis unable to detect displacement amount 7 between terminal electrodes 3and 5. The measurement involves a considerable amount of time. Inaddition, terminal electrode 5 of the flexible printed circuit board isusually formed by etching with a liquid agent and hence formed to have asection in a trapezoid shape as shown in FIG. 13. As a result, ameasurement error of several μm is caused, for example depending onwhich of positions A, B and C the operator regards as the end ofterminal electrode 5. Further, there is a variation in measurementresult of displacement amount 7 due to a difference in stretch amount ofterminal electrode 5 between compressed and non-compressed portions.Moreover, such manual measurement by the microscope does not immediatelyprovide a distance between central lines of terminal electrodes 5 atboth ends of the terminal electrode rows of flexible printed circuitboard 4, i.e., a total pitch. Thus, feedback as well as real timeelimination of variation in stretch amount are impossible.

In view of the above, the present invention aims at providing a mountingapparatus and mounting method which enables detection and adjustment ofa stretch amount of a flexible printed circuit board in a short periodof time, and which is capable of avoiding displacement inconsistency.

SUMMARY OF THE INVENTION

To achieve the above mentioned object, a mounting apparatus according toone aspect of the present invention includes: a heater head for bondingby thermocompression a display board and a flexible print circuit boardin such a way that a first terminal electrode row of the display boardand a second terminal electrode row of the flexible printed circuitboard are electrically connected; a heater head driving portion fordriving the heater head in such a way that the heater head compressesthe display board and flexible printed circuit board by a prescribedload; and a stretch amount controlling portion for adjusting a loadchange per unit of time after the heater head starts compressing theflexible printed circuit board by the heater head driving portion aswell as the time at which a required load is attained to control thestretch amount of the second terminal electrode row caused bythermocompression.

With the above described structure, the stretch amount of the flexibleprinted circuit board can be controlled by adjusting the load change andthe time at which the required load is attained. Thus, variation instretch amount which has conventionally been measured based on personaljudgement and experience of an operator can be eliminated. Thus,displacement inconsistency can be avoided.

A mounting apparatus according to another aspect of the presentinvention includes: a heater head for bonding by thermocompression adisplay board and a flexible printed circuit board in such a way that afirst terminal electrode row of the display board and a second terminalelectrode row of the flexible printed circuit board are electricallyconnected; a heater head driving portion for driving the heater head insuch a way that the heater head compresses the display board and theflexible printed circuit board by a prescribed load; and a stretchamount controlling portion for adjusting a speed at which the heaterhead driving portion drives the heater head toward the flexible printedcircuit board to control the stretch amount of the second terminalelectrode row caused by thermocompression.

With the above described structure, the speed at which the heater headis moved toward the flexible printed circuit board is adjusted andvariation in speed among compression cycles is controlled, whereby thestretch amount of the flexible printed circuit board can be controlled.As a result, displacement inconsistency can be avoided.

Preferably, the above described invention includes: a displacementamount detecting portion for detecting a displacement amount ofpositioning patterns formed on either side of the second terminalelectrode row with respect to reference patterns formed on either sideof the first terminal electrode row; a stretch amount calculatingportion for calculating the stretch amount of the second terminalelectrode row based on the displacement amount; and a correction amountcalculating portion for calculating a correction amount corresponding toa difference between the stretch amounts of the first and secondterminal electrode rows based on the stretch amount of the secondterminal electrode row.

With the above described structure, the correction amount can becalculated by the correction amount calculating portion, whereby thecorrection amount can be accurately found in a short period of timeunlike the conventional case of personal judgement and experience of theoperator.

In the above described invention, preferably, the stretch amountcontrolling portion controls by feeding back the correction amount. Withthis structure, the problem associated with variation in stretch amountis accurately alleviated in real time since correction is made based onactual data, rather than on personal judgement and experience of theoperator as in the conventional case.

Preferably, the above described invention includes a data holdingportion for holding data regarding a relationship between an operationparameter and a stretch amount of the second terminal electrode row. Thestretch amount controlling portion determines a necessary control methodfrom data held in the data holding portion for control. With thisstructure, a necessary control method is rapidly determined for control.In addition, a variety of data provides better control.

In a mounting method according to one aspect of the present invention, adisplay board and a flexible printed circuit board are bonded bythermocompression with use of a heater head in such a way that a firstterminal electrode row of the display board and a second terminalelectrode row of the flexible printed circuit board are electricallyconnected, where a load change per unit of time after the heater headstarts compressing against the flexible printed circuit board as well asthe time at which a required load is attained are controlled, so that astretch amount of the second terminal electrode row caused bythermocompression is controlled.

With the above described method, the load change and the time at whichthe required load is attained are adjusted to control the stretch amountof the flexible printed circuit board. Thus, variation in stretch amountwhich is conventionally measured based on personal judgement andexperience of the operator can be eliminated. Thus, displacementinconsistency can be avoided.

In a mounting method according to another aspect of the presentinvention, a display board and a flexible printed circuit board arebonded by thermocompression with use of a heater head in such a way thata first terminal electrode row of the display board and second terminalelectrode row of the flexible printed circuit board are electricallyconnected. A speed at which the heater head is moved toward the flexibleprinted circuit board is controlled, so that the stretch amount of thesecond terminal electrode row caused by thermocompression is controlled.

With the above described structure, the speed at which the heater headis moved toward the flexible printed circuit board is adjusted andvariation in speed during compression is controlled, so that the stretchamount of the flexible printed circuit board can be controlled. As aresult, displacement inconsistency can be avoided.

In the above described invention, preferably, control of the load changeand the time at which the required load is attained refers tosubstantially stabilizing the load change and the time at which therequired load is attained. With this structure, the stretch amount canbe stabilized with a relatively simple mechanism and displacementinconsistency can be alleviated.

In the above described invention, preferably, control of the load changeand the time at which the required load is attained refers toquantitative control to set the stretch amount at a desired value. Withthis structure, the stretch amount can be maintained at the desiredvalue by quantitative control. As a result, displacement inconsistencycan be alleviated.

Preferably, the above described invention includes: a displacementamount detecting step of detecting a displacement amount of positioningpatterns formed on either side of the second terminal electrode row withrespect to reference patterns formed on either side of the firstterminal electrode row; a stretch amount calculating step of calculatinga stretch amount of the second terminal electrode row based on thedisplacement amount; and a correction amount calculating step ofcalculating a correction amount corresponding to a difference betweenstretch amounts of the first and second terminal electrode rows based onthe stretch amount of the second terminal electrode row, wherequantitative control is performed by feeding back the correction amount.

With the above described structure, the correction amount can be rapidlyand objectively found unlike the conventional case where the correctionamount is measured based on personal judgement and experience of theoperator for feedback control. Thus, the requirements for real timeadjustment of stretch amount on a production line can be satisfied withno problem.

Preferably, the above described invention includes: a preliminarybonding step of preliminary fixing a relative position of the flexibleprinted circuit board and the heater head; a displacement amountdetecting step performed after the preliminary bonding step; and aregular bonding step performed after the displacement amount detectingstep. With this method, stable measurement is enabled since themeasurement is performed with the relative position fixed. The obtainedmeasurement result is made available for regular bonding, so that moreaccurate bonding is enabled.

Preferably, the above described invention includes: a relative positiondetermining step of determining a relative positional relationshipbetween reference patterns formed on either side of the first terminalelectrode row and a relative positional relationship between positionalpatterns formed on either side of the second terminal electrode row; apreliminary bonding step of preliminary fixing a relative position ofthe flexible printed circuit board and the heater head performed afterthe relative position determining step; a stretch amount calculatingstep of calculating a stretch amount of the second terminal electroderow based on information obtained by the relative position determiningstep; a correction amount calculating step of calculating a correctionamount corresponding to a difference between stretch amounts of thefirst and second terminal electrode rows based on the stretch amount ofthe second terminal electrode row; and a regular bonding step performedafter the preliminary bonding step. With this method, the stretch amountof the second terminal electrode row can be found even if a measurementoperation cannot be performed between the preliminary bonding step andthe regular bonding step, whereby proper control can be performed duringthe regular bonding.

The foregoing and other objects, features, aspects and advantages of thepresent invention will become more apparent from the following detaileddescription of the present invention when taken in conjunction with theaccompanying drawings.

FIG. 1 is a diagram shown in conjunction with a mounting operationaccording to a first embodiment of the present invention.

FIG. 2 is a top view showing thermocompressed components according tothe first embodiment of the present invention.

FIG. 3 is a schematic diagram showing a thermocompression apparatusaccording to the first embodiment of the present invention.

FIG. 4 is a schematic diagram showing a thermocompression apparatusaccording to a second embodiment of the present invention.

FIG. 5 is a schematic diagram showing a mounting apparatus according tothe second embodiment of the present invention.

FIG. 6 is a graph showing a load change when the mounting apparatusaccording to the second embodiment of the present invention is used.

FIG. 7 is a top view showing preliminary bonded components according toa third embodiment of the present invention.

FIG. 8 is a schematic diagram showing a thermocompression apparatusaccording to a fourth embodiment of the present invention.

FIG. 9 is a top view of components before preliminary bonding accordingto the fourth embodiment of the present invention.

FIG. 10 is a diagram shown in conjunction with a prior art mountingoperation.

FIG. 11 is a top view of thermocompressed components of the prior art.

FIG. 12 is a diagram showing in enlargement thermocompressed terminalelectrodes of the prior art.

FIG. 13 is a cross sectional view showing the terminal electrode.

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

Referring to FIGS. 1 to 3, a mounting apparatus according to the firstembodiment of the present invention will be described.

The mounting apparatus includes a heater head 80 for thermocompression,and a cylinder 20 as a heater head driving portion for driving heaterhead 80, as can be seen in FIG. 3. The mounting apparatus furtherincludes a control mechanism 21 as a stretch amount controlling portionfor adjusting a load change per unit of time after heater head 80 startscompression of a flexible printed circuit board 4 (see FIG. 1) as wellas a time at which a required load is attained. The functions of thesecomponents will be detailed afterwards.

As shown in FIG. 1, the mounting apparatus mounts a liquid crystaldisplay 2 onto a flexible printed circuit board 4 by bonding bythermocompression terminal electrodes 3 of liquid crystal display 2containing a liquid crystal layer 1 and terminal electrodes 5 offlexible printed circuit board 4. For example, flexible printed circuitboard 4 includes terminal electrodes 5 densely formed in stripes in abase material of polyimide. FIG. 2 shows only terminal electrode 51 and52 at both ends of the stripe pattern as terminal electrodes 5, notshowing any intervening terminal electrode. Positioning patterns 131 and132 are formed on both sides of the terminal electrode row of flexibleprinted circuit board 4. On the side of liquid crystal display 2,reference patterns 141 and 142 are formed on both sides of the terminalelectrode row. A pitch 18 between reference patterns 141 and 142 isknown in designing flexible printed circuit board 4. Note that “a pitch”herein refers to a distance between centers.

Even if the centers of positioning patterns 131 and 132 respectivelycoincide with those of reference patterns 141 and 142 before bonding,after thermocompression, they are displaced due to stretching offlexible printed circuit board 4. As a result, relative displacementamounts 151 and 152, i.e., differences in position of centers, arecaused as shown in FIG. 2.

Referring to FIG. 1, relative displacement amounts 151 and 152,difference in position of centers, are caused as shown in FIG. 2.

Referring to FIG. 1, relative displacement amounts 151 and 152 aresensed by an image pickup device 16 (e.g., a camera) provided in astretch amount detecting unit 24 as a displacement amount detectingportion, and then quantitatively detected by an image processingapparatus 17. If preliminary bonding is performed before regularbonding, the image pickup and detection may be performed in any stage ofthe process, either before or after preliminary bonding.

In a geometrical relationship shown in FIG. 2, relative displacementamounts 151 and 152 are quantatively detected by stretch amountdetecting unit 24 and subjected to an operation process with use of thestretch amount detecting portion. Based on relative displacement amounts151 and 152, a stretch rate of pitch 18 between the positioning patternson both sides of flexible printed circuit board 4 is calculated. Thestretch amount calculating portion may be formed for example of a CPU(Central Processing Unit) and a memory with a combination of an LSI(Large Scale Integration) chips or the like. Note that a CPU providedfor the other purpose may be used.

Based on the stretch rate found by the stretch amount calculatingportion, a stretch amount of pitch 11 between terminal electrodes 51 and52 at either end of flexible printed circuit board 4 is calculated.Based on the stretch amount of pitch 11, an operation process isperformed by a correction amount calculating portion to find adifference between an expected stretch amount and the actual stretchamount, i.e., a correction amount. The correction amount isrepresentative of a sum of a distance 191 between center lines ofterminal electrodes 31 and 51 and a distance 192 between center lines ofterminal electrodes 32 and 52. Like the above described stretch amountcalculating portion, the correction amount calculating portion can alsobe formed of LSI chips or the like.

FIG. 3 partially shows the mounting apparatus of the present embodiment.The heater tool is also cylinder-driven as in conventional case, but hascontrol mechanism 21 for electrically feeding back the pressure and flowof air to be supplied to cylinder 20 as a heater driving portion fordriving heater head 80. Control mechanism 21 converts pressure variationin cylinder 20 to a corresponding electric signal, based on which itcontrols pressure and flow of air to be supplied to cylinder 20.Examples of control mechanism 21 include a commercially availableelectropneumatic regulator manufactured by SMC Corporation. Controlmechanism 21 adjusts a load change per unit of time after heater head 80starts compression of flexible printed circuit board 4 as well as a timeat which a required load is attained.

With the mounting apparatus of the present embodiment, image pickupdevice 16 as a displacement amount detecting portion detects relativedisplacement amounts 151 and 152, and the stretch amount calculatingportion and correction amount calculating portion are used to find acorrection amount. Since information on the correction amount can bemade available to the stretch amount controlling portion, the stretchamount can be adjusted much faster than in the conventional case.

In the present embodiment, the mounting apparatus has been described ashaving not only the heater head driving portion and the stretch amountcontrolling portion, but also the displacement amount detecting portion,stretch amount calculating portion, and correction amount calculatingportion. In this case, preferably, information on the resultantcorrection amount is fed back for control.

However, even if the displacement amount detecting portion, stretchamount calculating portion and correction amount calculating portion arenot provided, the presence of the heater head, heater head drivingportion and stretch amount controlling portion would provide control ofthe stretch amount to produce a given effect.

Note that the stretch amount controlling portion herein used controlsthe pressure and flow of air to be supplied to cylinder 20 to adjust theload change per unit of time after heater head 80 starts compression offlexible printed circuit board 4 as well as the time at which therequired load is attained. This is because adjustment of the load changeper unit of time after starting compression and the time at which therequired load is attained provides adjustment of the stretch amount offlexible printed circuit board 4.

If it is difficult to perform feed back control, the load change perunit of time after heater head 80 starts compression of flexible printedcircuit board 4 and the time at which the required load is attained canbe substantially fixed to stabilize to some extent the stretch amount,which is preferable.

Second Embodiment

Referring to FIGS. 1, 2 and 4 to 6, a mounting apparatus according tothe second embodiment of the present invention will be described.

Referring to FIG. 4, the mounting apparatus includes a heater head 80for thermocompression, and a cylinder 20 and a motor 22 as a heater headdriving portion for driving heater head 80. The mounting apparatusfurther includes a control mechanism 21 as a stretch amount controllingportion for adjusting a speed at which cylinder 20 and motor 22 driveheater head 80 toward flexible printed circuit board 4 (see FIG. 1).

The operation up to calculation of a correction amount is the same as inthe first embodiment. In addition, the presence of the displacementamount detecting portion, stretch amount calculating portion andcorrection amount calculating portion is also the same as in the firstembodiment. Note that control mechanism 21 adjusts the speed at whichheater head 80 is moved toward flexible printed circuit board 4.

Since the heater head driving portion is provided with motor 22, thespeed of heater head 80 and the stretch amount of flexible printedcircuit board 4 can be adjusted.

Motor 22 in the heater head driving portion provides a greater loadchange per unit of time after starting compression. FIG. 6 shows a loadchange shortly after compression of flexible printed circuit board 4 isstarted. Curves 12 and 23 respectively correspond to the cases withoutand with motor 22. Although it is known that flexible printed circuitboard 4 stretches by application of heat, it becomes less stretchy byapplication of pressure. Then, the application times of various levelsof pressure are adjusted according to the load change per unit of timeto control the stretch amount.

In addition, use of motor 22 leads to high repeatability of the heaterhead movement. As a result, the stretch amount of flexible printedcircuit board 4 exhibits higher repeatability, which is advantageous notonly to the present embodiment but also to the first embodiment.

If the mounting apparatus of the present invention is adapted to connectthermocompression apparatus 25 to stretch amount detecting unit 24 as inFIG. 5 to provide real time feed back control, the problem associatedwith displacement inconsistency can be rapidly eliminated on aproduction line, which is preferable. In addition, higher repeatabilityis provided.

In FIG. 5, the thermocompression apparatus of the first embodiment maybe employed in place of thermocompression apparatus 25.

Third Embodiment

Referring to FIG. 7, a mounting apparatus according to the thirdembodiment of the present invention will be described. In the presentembodiment, preliminary bonding is performed and followed by imagepickup and detection. The term “preliminary bonding” means that arelative positional relationship between liquid crystal display 2 andflexible printed circuit board 4 is preliminary fixed before “regularbonding” which provides for permanent bonding of liquid crystal display2 and flexible printed circuit board 4.

Referring to FIG. 7, flexible printed circuit board 4 is preliminarybonded to liquid crystal display 2. Although FIG. 7 is similar to FIG. 2of the first embodiment, in FIG. 7, flexible printed circuit board 4 isnot yet thermally expanded to a large extent in the width directionsince it has merely been subjected to preliminary bonding.

After the preliminary bonding, relative displacement amounts 351 and 352of positioning patterns 131 and 132 respectively with respect toreference patterns 141 and 142 of liquid crystal display 2 are detectedby image processing apparatus 17 provided with an image pickup device16. Based on the resultant relative displacement amounts 351 and 352, arate at which a pitch 38 between positioning patterns 131 and 132 shouldstretch during subsequent regular bonding (hereinafter simply referredto as “a required stretch rate”) is calculated. Based on the obtainedrequired stretch rate, a current stretch amount between terminalelectrodes 51 and 52 at both ends of the terminal electrodes of flexibleprinted circuit board 4 is calculated, and a difference between a designvalue and the current stretch amount is calculated to find a correctionamount of the pitch between terminal electrodes 51 and 52.

In the mounting apparatus, curve data representing a required load as inthe graph of FIG. 6 is stored as preliminary verified data for variousvalues of correction amount of the pitch between terminal electrodes 51and 52. Referring to data for the currently obtained correction amountof pitch between terminal electrodes 51 and 52 and performing anoperation process if necessary, a desirable control method of the heaterhead is determined. The heater head is controlled to quantitativelycontrol the stretch amount of pitch between terminal electrodes 51 and52.

Fourth Embodiment

Referring to FIGS. 8 and 9, a mounting apparatus according to the fourthembodiment of the present invention will be described. In the presentembodiment, preliminary bonding is performed after image pickup anddetection.

FIG. 8 shows the mounting apparatus before preliminary bonding. Liquidcrystal display 2 and flexible printed circuit board 4 are close to eachother, but not yet overlap when viewed from above. In this state, imagepickup device 16 provided in stretch amount detecting unit 24 takesimages of front edge portions of liquid crystal display 2 and flexibleprinted circuit board 4. The resultant images are as shown in FIG. 9.Positioning patterns 131 and 132 of flexible printed circuit board 4 aredetected by image processing apparatus 17 and a pitch 38 betweenpositioning patterns 131 and 132 is obtained. Further, referencepatterns 141 and 142 of liquid crystal display 2 are detected by imageprocessing apparatus 17, and a pitch 39 between reference patterns 141and 142 is obtained. A required stretch rate of pitch 38 is calculatedfrom pitches 38 and 39. The subsequent operation is the same as in thethird embodiment.

According to the present invention, the stretch amount of the flexibleprinted circuit board can be controlled. Thus, the stretch amount can bemeasured accurately and rapidly without relying on personal judgementand experience of the operator, whereby variation in stretch amount canbe eliminated. As a result, displacement inconsistency can be avoided.

Although the present invention has been described and illustrated indetail, it is clearly understood that the same is by way of illustrationand example only and is not to be taken by way of limitation, the spiritand scope of the present invention being limited only by the terms ofthe appended claims.

What is claimed is:
 1. A mounting apparatus, comprising: a heater headfor bonding by thermocompression a display board and a flexible printedcircuit board in such a way that a first terminal electrode row of saiddisplay board and a second terminal electrode row of said flexibleprinted circuit board are electrically connected; heater head drivingmeans for driving said heater head in such a way that said heater headcompresses said display board and said flexible printed circuit board bya prescribed load; and stretch amount controlling means for adjusting aload change per unit of time after said heater head driving means startscompressing said heater head against said flexible printed circuit boardas well as a time at which a required load is attained to control astretch amount of said second terminal electrode row caused by thethermocompression.
 2. The mounting apparatus according to claim 1,further comprising: displacement amount detecting means for detecting adisplacement amount of positioning patterns formed on either side ofsaid second terminal electrode row with respect to reference patternsformed on either side of said first terminal electrode row; stretchamount calculating means for calculating the stretch amount of saidsecond terminal electrode row based on said displacement amount; andcorrection amount calculating means for calculating a correction amountcorresponding to a difference between stretch amounts of said first andsecond terminal electrode rows based on the stretch amount of saidsecond terminal electrode row.
 3. The mounting apparatus according toclaim 2, wherein said stretch amount controlling means controls byfeeding back said correction amount.
 4. The mounting apparatus accordingto claim 2, further comprising data holding means for holding dataregarding a relationship between an operation parameter and the stretchamount of said second terminal electrode row, wherein said stretchamount controlling means determines a necessary control method from dataheld in said data holding means based on said correction amount forcontrol.
 5. A mounting apparatus, comprising: a heater head bonding bythermocompression a display board and a flexible printed circuit boardin such a way that a first terminal electrode row of said display boardand a second terminal electrode row of said flexible printed circuitboard are electrically connected; heater head driving means for drivingsaid heater head in such a way that said heater head compresses saiddisplay board and said flexible printed circuit board by a prescribedload; and stretch amount controlling means for adjusting a speed atwhich said heater head driving means drives said heater head toward saidflexible printed circuit board to control a stretch amount of saidsecond terminal electrode row caused by the thermocompression.
 6. Themounting apparatus according to claim 5, further comprising:displacement amount detecting means for detecting a displacement amountof positioning patterns formed on either side of said second terminalelectrode row with respect to reference patterns formed on either sideof said first terminal electrode row; stretch amount calculating meansfor calculating the stretch amount of said second terminal electrode rowbased on said displacement amount; and correction amount calculatingmeans for calculating a correction amount corresponding to a differencebetween stretch amounts of said first terminal electrode row and saidsecond terminal electrode row based on the stretch amount of said secondterminal electrode row.
 7. The mounting apparatus according to claim 6,wherein said stretch amount controlling means controls by feeding backsaid correction amount.
 8. The mounting apparatus according to claim 6,further comprising data holding means for holding data regarding arelationship between an operation parameter and the stretch amount ofsaid second terminal electrode row, wherein said stretch amountcontrolling means determines a necessary control method from data heldin said data holding means based on said correction amount for control.